From owner-freebsd-acpi@FreeBSD.ORG Fri May 26 13:57:30 2006 Return-Path: X-Original-To: freebsd-acpi@freebsd.org Delivered-To: freebsd-acpi@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9BD4716A428 for ; Fri, 26 May 2006 13:57:30 +0000 (UTC) (envelope-from nate@root.org) Received: from ylpvm12.prodigy.net (ylpvm12-ext.prodigy.net [207.115.57.43]) by mx1.FreeBSD.org (Postfix) with ESMTP id 8CF1943D5A for ; Fri, 26 May 2006 13:57:29 +0000 (GMT) (envelope-from nate@root.org) Received: from pimout5-ext.prodigy.net (pimout5-int.prodigy.net [207.115.4.21]) by ylpvm12.prodigy.net (8.12.10 outbound/8.12.10) with ESMTP id k4QDvLuk022404 for ; Fri, 26 May 2006 09:57:26 -0400 X-ORBL: [71.139.38.236] Received: from [10.0.5.50] (ppp-71-139-38-236.dsl.snfc21.pacbell.net [71.139.38.236]) by pimout5-ext.prodigy.net (8.13.6 out.dk/8.13.6) with ESMTP id k4QDvNd1087122; Fri, 26 May 2006 09:57:24 -0400 Message-ID: <447708E6.7010205@root.org> Date: Fri, 26 May 2006 06:55:50 -0700 From: Nate Lawson User-Agent: Thunderbird 1.5.0.2 (Windows/20060308) MIME-Version: 1.0 To: Andriy Gapon References: <4475C74C.2080204@icyb.net.ua> In-Reply-To: <4475C74C.2080204@icyb.net.ua> Content-Type: text/plain; charset=KOI8-U; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-acpi@freebsd.org, Nate Lawson Subject: Re: nforce2 cpufreq X-BeenThere: freebsd-acpi@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: ACPI and power management development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 26 May 2006 13:57:31 -0000 Andriy Gapon wrote: > I've recently had a sudden urge to investigate power saving / cpu > throttling options for my desktop Athlon XP system. > It seems that the CPU itself does not provide any interfaces for that, > at least neither of acpi_perf/acpi_throttle/cpufreq seem to detect > anything interesting for them. > Or am I mistaken and doing something wrong ? > > Anyway, my MB is based on nForce2 chipset and I found out that Linux has > cpufreq-nforce2 module that works in their cpufreq framework: > http://www.hasw.net/linux/ > > It seems that that module works by using nForce2 PCI interface for > querying and changing FSB frequency. It also seems that the code is > rather simple and obvious in its logic (save for allegedly > reverse-engineered constants). Not sure though how easy it is to port > that to FreeBSD cpufreq framework. > But the question that I really would like to ask is the following: is it > a proper way to do cpufreq stuff by changing FSB frequency ? Would that > approach fit into our framework ? And finally, would it have any > positive temperature/power consumption effects ? > It's really easy to do. Just see the sys/dev/cpufreq/ichss.c file. -- Nate